Europaean Late Cretaceous vertebrate paleobiogeography

The ancient vertebrates of Iharkút and the European biogeography during the Cretaceous

Discovered in 2000, the Iharkút vertebrate locality provided almost 10.000 bones and teeth of at least 30 different vertebrate groups including fishes, amphibians, turtles, crocodiles, dionsaurs and birds. Although the Iharkút fauna is similar at family level to the other Late Cretaceous European fauna, genera and species are different in most cases. Some species show similarities with forms from quite different regions: the remains referred to an abelisaurid theropod dinosaur are similar to those of abelisaurids from South America and Africa, the basal ceratopsian dinosaur Ajkaceratops is most similar to the bagaceratopsid ceratopsian from Central Asia, and the small lizard, Bicuspidon from Iharkút shows affinities with a North American species. This story becomes more interesting in the light of the paleogeographical background: Europe was an archipelago with smaller and larger islands (including the Bakony Mountains) rather than a large land for an extremely complex and diverse ecosystem.

The European archipelago during the Late Cretaceous (top) and the timescale with the age of the Iharkút dinosaurs (bottom).

One of the main goals of our research group is to detect the affinities of the Iharkút species with those of other European and non-European faunas. It is important to know, which are their closest relatives and which of the Iharkút elements are completely unique among European forms (e.g Ajkaceratops). How and from where did they reach the Iharkút land is also among the main objects to be answered. Results of the last 13 years of research indicate that the 85 million years old Iharkút ecosystem was composed of a mixed fauna including not only forms with European origin (e.g. the rhabdodontid Mochlodon, the peculiar crocodile Iharkutosuchus) but also forms with North American, Asian and Gondwanan (mainly Africa+South America) origin.